Although you can enjoy much of this website without javascript, we highly recommend that you enable it
in order to experience all available features.

Cookies on What Doctors Don't Tell You

We set cookies so you can manage your account and navigate the site, and to remember your cookie preferences so that you don't keep getting this message. To accept cookies, just keep browsing,
otherwise use the links on the right to adjust your cookie settings or find out more.

The Wikipedia entry for Ecklonia cava (EC) is barely three lines long. Yet, this little-known brown seaweed is making waves in the supplement industry and is currently being touted as the biggest nutritional breakthrough in the last two decades.

Extracts of EC have been the subject of intense scientific study in recent years, and they have now found their way into supplements claiming to boost immunity, heart health, energy levels, brain function and more. According to its proponents, EC is the most powerful antioxidant you can get and the answer to everything from Alzheimer's to insomnia and heart disease.

A closer look at this strange-sounding seaweed can determine whether what we know so far lives up to the hype.

What is Ecklonia cava?

EC is an edible brown seaweed found abundantly in the coastal waters off Japan and Jeju (Cheju) Island, part of South Korea. Known commonly as kajime in Japanese and kamtae in Korean, it's been used in these regions for generations as a food ingredient as well as a supplement for animal feeds and fertilizers (Nutr Res Pract, 2011; 5: 93-100).

Recently, EC has been recognized as a rich source of phlorotannins-a subgroup of tannins-which are antioxidant compounds also known as 'polyphenols' that are found exclusively in brown algae. Research shows that these phlorotannins exhibit various beneficial biological activities, including antioxidant, anticancer, antidiabetic, antihypertensive and antiallergic effects (Biofactors, 2010; 36: 408-14).

As a result, scientists have been investigating the potential of EC for a range of health conditions and applications-and the findings so far are encouraging.

Laboratory findings

Most of the research on EC to date has been conducted in the lab in test-tubes or in animals. Although this is a vital part of the research process, it unfortunately also means that the results may not apply clinically to humans. Still, the studies suggest that EC may be useful for the following conditions.

Osteoarthritis. In a number of test-tube experiments, phlorotannin-rich extracts of EC showed a range of activities that may have value in the treatment of osteoarthritis. The extracts appeared to counteract the production of the various inflammatory mediators involved in the condition-such as reactive oxygen species and prostaglandins-a finding that is deserving of further study, the researchers said (Res Commun Mol Pathol Pharmacol, 2004; 115-116: 77-95; Arch Pharm Res, 2006; 29: 165-71).

Diabetes. In a mouse model of diabetes, an extract of EC rich in the phlorotannin dieckol was tested against the antidiabetic drug rosiglitazone and a control as placebo. Both the drug and the EC extract significantly reduced blood glucose and insulin levels compared with the control, but only the EC extract improved glucose (sugar) tolerance. Moreover, the extract showed potent antioxidant activity and improved lipid (fat) metabolism, other factors indicativeof an antidiabetic effect (Food Chem Toxicol, 2011 Dec 30; Epub ahead of print).

Neuropsychiatric disorders. A study by the Korea Food Research Institute concluded that EC is a good candidate as a possible effective treatment of neuropsychiatric disorders such as anxiety and insomnia. In this mouse study, an extract of EC was found to have depressive effects on the central nervous system, thereby inducing sleep and controlling seizures (Biosci Biotechnol Biochem, 2012 Jan 7; Epub ahead of print).

Flu. A number of the phlorotannins in EC, including dieckol, eckol and phloroglucinol, have been found to inhibit neuraminidase (NA), which plays a critical role in the lifecycle of the influenza virus, and is the primary target of several anti-flu drugs. Not only did each of the extracts show extremely high NA-inhibitory activity on their own, but they also worked in synergy with the antiviral drug oseltamivir to enhance its NA-inhibitory effects (J Agric Food Chem, 2011; 59: 6467-73).

Alzheimer's disease. An EC extract was recently shown to suppress the production and build-up of fibrils of beta-amyloid peptides, the accumulation of which in the brain is one ofthe hallmarks of Alzheimer's. The results show, for the first time, EC's potential in treating this debilitating dementia-related disorder, the researchers said (Food Chem Toxicol, 2011; 49: 2252-9).

Hypertension. Angiotensin-1-converting enzyme (ACE) inhibitors are commonly used to treat hypertension (high blood pressure), but this class of drugs comes with a multitude of side-effects. However, phlorotannins from EC, especially dieckol, have demonstrated natural ACE-inhibitory activity, an indication of their potential in the treatment of hypertension and heart disease (Nutr Res Pract, 2011; 5: 93-100).

MRSA infections. The antibacterial activity of EC was investigated against the superbugs methicillin-resistant Staphylococcus aureus (MRSA) in a study by researchers at Wonkwang University in Souh Korea. Eckol, one of the phlorotannins in EC, showed strong antibac-terial activity against all S. aureus strains-resistant or not. It was also effective against several Salmonella species and strains (Foodborne Pathog Dis, 2010; 7: 435-41).

Breast cancer. The phlorotannin phloroglucinol holds promise as an anticancer agent. In a test-tube study of human breast-cancer cells, phloroglucinol derivatives isolated from EC were found to halt the growth of the cancer cells by inducing apoptosis-natural programmed cell death (Food Chem Toxicol, 2009; 47: 1653-8).

Clinical trials so far

There appear to be only two published clinical trials of EC, but the good news is that both of them were randomized, placebo-controlled trials-the sort that are considered the 'gold standard' for scientific evaluation. The most recent one, which has been published online ahead of print, looked at the effects of supplementing with EC polyphenols (ECP) on 97 overweight Korean men and women.

The participants were randomly allocated to one of three groups and given low-dose ECP (72 mg/ day), high-dose ECP (144 mg/day) or a placebo. After 12 weeks, the researchers reported that both ECP groups showed significant decreases in BMI (body mass index), body fat ratio, waist circum-ference, waist-to-hip ratio, total cholesterol and 'bad' low-density lipoprotein (LDL) cholesterol compared with the placebo group. The high-dose ECP group also showed a significant increase in 'good' high-density lipoprotein (HDL) cholesterol as well as significant decreases in blood glucose levels and systolic blood pressure. What's more, ECP supplementation was not associated with any significant adverse effects (Phytother Res, 2011 Jun 30; doi: 10.1002/ptr.3559).

The other study was conducted on 20 male college students, who were randomly given either an ECP-supplemented drink or a placebo drink to test the effects on physical endurance. Participants then had to perform exercise trials, followed by a one-week interval, after which they were given the other (ECP or placebo) drink and exercise-tested again.

The researchers found that the students were able to exercise for significantly longer before becoming exhausted with the ECP drink compared with the placebo drink (Int J Sport Nutr Exerc Metab, 2010; 20: 72-9).

The bottom line

In theory, EC may be helpful against a variety of diseases and conditions, as the studies so far indicate that it has a wide range of beneficial biological effects. However, most of the research is still in the preliminary stages and has only been done in the laboratory or in animals, so we don't yet know if the results will be as positive in humans. Although what clinical trials there are have so far been encouraging, much more research is needed-especially with regards to long-term effects and safety, and dosages.

That said, research into the benefits of E. cava and other seaweeds is an exciting area of science. Numerous compounds from these modest marine plants are showing their potential to be as powerful as pharmaceuticals, but with a more diverse range of beneficial actions. No doubt we'll be hearing a lot more about this super seaweed in the future.